In respiratory therapy (e.g., treatment of Sleep Disordered Breathing (SDB) such as Obstructive Sleep Apnea (OSA) with Continuous Positive Airway Pressure (CPAP) or Non-Invasive Positive Pressure Ventilation (NIPPV)) where breathable gas is delivered to a patient interface (e.g., cushion, nasal “cradle,” etc.) under pressure, a good seal is typically maintained between the patient interface and the patient's face. Leaks between the patient interface and the patient's face can reduce the effectiveness of, and compliance with, the therapy, as the prescribed treatment parameters are not being maintained.
Leaks are especially prone to occur as the patient moves during the night. Movement of and drag on the air delivery tube as the patient turns or moves can alter the positioning and alignment of the patient interface with respect to the patient's face. This movement can be translated or transferred to the seal formed between the patient interface and the patient's face which may in turn create a leak in the seal. Thus, while the patient interface may initially be leak free when attached to the patient, leaks are prone to develop later in the night as the patient moves in bed which may cause the patient to waken rendering the therapy ineffective.
In certain mask designs, air pressure from within a mask chamber (or pressure chamber) may act on the underside of a mask seal, e.g., a thin flap, to urge the flap into sealing position. However in other mask designs, this air pressure effect may not impact on the seal effectiveness.
Accordingly, there is a continuous need in the art for patient interface systems, accessories, etc. that ensure a good seal between the patient interface and the patient's face is maintained.